Works like "python -m venv path" and creates a rudimentary virtual
environment for the Unix port:
- sets MICROPYPATH
- copies the micropython binary to venv/bin/micropython which is in $PATH
- installs mip & mip-cmdline in the venv
Using the venv is the same as for CPython -- source the activate script to
enter, and call the deactivate function to leave.
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>